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Java > Open Source Codes > org > jboss > invocation > jrmp > interfaces > JRMPInvokerProxy


1 /*
2 * JBoss, Home of Professional Open Source
3 * Copyright 2005, JBoss Inc., and individual contributors as indicated
4 * by the @authors tag. See the copyright.txt in the distribution for a
5 * full listing of individual contributors.
6 *
7 * This is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * This software is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this software; if not, write to the Free
19 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21 */
22 package org.jboss.invocation.jrmp.interfaces;
23
24 import java.io.IOException JavaDoc;
25 import java.io.Externalizable JavaDoc;
26 import java.io.ObjectInput JavaDoc;
27 import java.io.ObjectOutput JavaDoc;
28 import java.rmi.ConnectException JavaDoc;
29 import java.rmi.MarshalledObject JavaDoc;
30 import java.rmi.NoSuchObjectException JavaDoc;
31 import java.rmi.RemoteException JavaDoc;
32 import java.rmi.ServerException JavaDoc;
33 import java.rmi.server.RemoteObject JavaDoc;
34 import java.rmi.server.RemoteStub JavaDoc;
35 import javax.transaction.TransactionRolledbackException JavaDoc;
36 import javax.transaction.SystemException JavaDoc;
37
38 import org.jboss.invocation.Invocation;
39 import org.jboss.invocation.Invoker;
40 import org.jboss.invocation.MarshalledInvocation;
41 import org.jboss.tm.TransactionPropagationContextFactory;
42 import org.jboss.tm.TransactionPropagationContextUtil;
43
44 /**
45  * JRMPInvokerProxy, local to the proxy and is capable of delegating to
46  * the JRMP implementations
47  *
48  * @author <a HREF="mailto:marc.fleury@jboss.org">Marc Fleury</a>
49  * @author <a HREF="mailto:scott.stark@jboss.org">Scott Stark</a>
50  * @version $Revision: 37459 $
51  */
52 public class JRMPInvokerProxy
53    implements Invoker, Externalizable JavaDoc
54 {
55    /** Serial Version Identifier. @since 1.7.2.4 */
56    private static final long serialVersionUID = -3713605626489646730L;
57    // Attributes ----------------------------------------------------
58
59    // Invoker to the remote JMX node
60 protected Invoker remoteInvoker;
61
62    /**
63     * max retries on a ConnectException.
64     */
65    public static int MAX_RETRIES = 10;
66
67    /**
68     * Exposed for externalization.
69     */
70    public JRMPInvokerProxy()
71    {
72       super();
73    }
74
75    /**
76     * Create a new Proxy.
77     *
78     * @param container The remote interface of the container invoker of the
79     * container we proxy for.
80     */
81    public JRMPInvokerProxy(final Invoker remoteInvoker)
82    {
83       this.remoteInvoker = remoteInvoker;
84    }
85
86    /**
87     * The name of of the server.
88     */
89    public String JavaDoc getServerHostName() throws Exception JavaDoc
90    {
91       return remoteInvoker.getServerHostName();
92    }
93
94    /**
95     * ???
96     *
97     * @todo: MOVE TO TRANSACTION
98     *
99     * @return the transaction propagation context of the transaction
100     * associated with the current thread.
101     * Returns <code>null</code> if the transaction manager was never
102     * set, or if no transaction is associated with the current thread.
103     */
104    public Object JavaDoc getTransactionPropagationContext()
105       throws SystemException JavaDoc
106    {
107       TransactionPropagationContextFactory tpcFactory = TransactionPropagationContextUtil.getTPCFactoryClientSide();
108       return (tpcFactory == null) ? null : tpcFactory.getTransactionPropagationContext();
109    }
110
111    /**
112     * The invocation on the delegate, calls the right invoker. Remote if we are remote,
113     * local if we are local.
114     * @todo Shouldn't we unwrap _ALL_ RemoteExceptions?
115     */
116    public Object JavaDoc invoke(Invocation invocation)
117       throws Exception JavaDoc
118    {
119       // We are going to go through a Remote invocation, switch to a Marshalled Invocation
120 MarshalledInvocation mi = new MarshalledInvocation(invocation);
121
122       // Set the transaction propagation context
123 // @todo: MOVE TO TRANSACTION
124 mi.setTransactionPropagationContext(getTransactionPropagationContext());
125
126       // RMI seems to make a connection per invocation.
127 // If too many clients are making an invocation
128 // at same time, ConnectionExceptions happen
129 for (int i = 0; i < MAX_RETRIES; i++)
130       {
131          try
132          {
133             MarshalledObject JavaDoc result = (MarshalledObject JavaDoc) remoteInvoker.invoke(mi);
134             return result.get();
135          }
136          catch (ConnectException JavaDoc ce)
137          {
138             if (i + 1 < MAX_RETRIES)
139             {
140                Thread.sleep(1);
141                continue;
142             }
143             throw ce;
144          }
145          catch (ServerException JavaDoc ex)
146          {
147             // Suns RMI implementation wraps NoSuchObjectException in
148 // a ServerException. We cannot have that if we want
149 // to comply with the spec, so we unwrap here.
150 if (ex.detail instanceof NoSuchObjectException JavaDoc)
151             {
152                throw (NoSuchObjectException JavaDoc) ex.detail;
153             }
154             if (ex.detail instanceof TransactionRolledbackException JavaDoc)
155             {
156                throw (TransactionRolledbackException JavaDoc) ex.detail;
157             }
158             if (ex.detail instanceof RemoteException JavaDoc)
159             {
160                throw (RemoteException JavaDoc) ex.detail;
161             }
162             throw ex;
163          }
164       }
165       throw new Exception JavaDoc("Unreachable statement");
166    }
167
168    /**
169     * Externalize this instance and handle obtaining the remoteInvoker stub
170     */
171    public void writeExternal(final ObjectOutput JavaDoc out)
172       throws IOException JavaDoc
173    {
174       /** We need to handle obtaining the RemoteStub for the remoteInvoker
175        * since this proxy may be serialized in contexts that are not JRMP
176        * aware.
177        */
178       if( remoteInvoker instanceof RemoteStub JavaDoc )
179       {
180          out.writeObject(remoteInvoker);
181       }
182       else
183       {
184          Object JavaDoc replacement = RemoteObject.toStub(remoteInvoker);
185          out.writeObject(replacement);
186       }
187    }
188
189    /**
190     * Un-externalize this instance.
191     *
192     */
193    public void readExternal(final ObjectInput JavaDoc in)
194       throws IOException JavaDoc, ClassNotFoundException JavaDoc
195    {
196       remoteInvoker = (Invoker) in.readObject();
197    }
198 }
199
200
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